The clinical and laboratory findings in 15 patients with septic discitis are reported. The clinical picture was that of a sub-acute illness characterized by back pain, spinous process tenderness, and sciatic nerve root irritation. There was a considerable delay from clinical presentation to diagnosis (average 14 wk). The erythrocyte sedimentation rate was the most useful diagnostic laboratory blood test and the best indicator of disease activity. The relative value of plain radiographs, tomography, and radionuclide bone scans is discussed. Needle aspiration of the disc space was found to be a useful diagnostic test. We found that a diagnosis of septic discitis could be made even in the absence of positive bacterial cultures from various biologic fluids or from the disc space. Long-term oral and intravenous antibiotic therapy with controlled rest resulted in a favourable outcome.